Nonlocal Piezoresponse of LaAlO3/SrTiO3 Heterostructures

TL;DR

This study investigates the hysteretic piezoelectric response in LaAlO3/SrTiO3 heterostructures using nonlocal piezoelectric force microscopy, revealing environmental and electrical influences on the response and proposing a physical model.

Contribution

The paper introduces a detailed nonlocal PFM analysis of LaAlO3/SrTiO3 heterostructures and a physical model explaining the hysteretic behavior under different conditions.

Findings

Hysteretic piezoresponse observed in heterostructures

Hysteresis suppressed in vacuum or grounded interface

Physical model accounts for environmental and electrical effects

Abstract

The hysteretic piezoelectric response in LaAlO3/SrTiO3 heterostructures can provide important insights into the mechanism for interfacial conductance and its metastability under various conditions. We have performed a variety of nonlocal piezoelectric force microscopy experiments on 3 unit cell LaAlO3/SrTiO3 heterostructures. A hysteretic piezoresponse is observed under various environmental and driving conditions. The hysteresis is suppressed when either the sample is placed in vacuum or the interface is electrically grounded. We present a simple physical model which can account for the observed phenomena.